Garments and footwear with flashing lights have been popular for a number of reasons, including safety, an attractive appearance and simply for a novelty effect.
Lighting units for clothing and footwear have typically included a light source, such as one or more light-emitting diodes, a power source, such as a battery and a switch to cause the power source to be connected to the light or lights. Often such units will include electronic circuits which can control the time such lights are actually illuminated, which limits the power consumption, saving the battery. Short-term flashing often makes the display more visible, adding to the safety provided by the units. It also makes a more attractive eye-catching display.
A number of different types of lighting units or circuits have been described in the prior art. U.S. Pat. No. 4,158,922 to Dana III includes a mercury switch that responds to movements of the foot to turn a light on and off. A mercury switch operated system is also taught in U.S. Pat. No. 4,848,009 to Rogers.
Various arrangements have been developed for minimizing battery drain. Applicant's earlier U.S. Pat. No. 5,477,435 issued Dec. 19, 1995, now RE 37,220E, shows a light module with an LED having one terminal in contact with one side of a wafer battery, and the other terminal spaced away from the battery but including a weight which will cause the upper terminal to move by inertia in response to a shoe striking a surface to contact the battery to illuminate the LED. In this way, the LED is not illuminated and does not draw power from the battery when the module is at rest. Other modules for illuminating lights in footwear are shown in U.S. Pat. Nos. 5,408,764 and 5,932,975. U.S. Pat. No. 5,932,975 also includes microcircuits with a photosensitive switch to cause illumination to fade and then shut off entirely with full daylight. This is one of a number of battery-saving arrangements in the art.
One kind of switch in common usage is a spring switch which consists of an elongated coil of wire which has one end connected to one terminal in an electrical circuit and the opposite end cantilevered over a second terminal in the circuit. With the impact of the footwear against a surface or movement of body members carrying the switch, the spring will tend to bounce against the second terminal a number of times, thereby producing a series of positive or negative going electrical spikes or pulses.
Another type of switch which has been used in the above-described application is similar to a mercury switch but using a ball bearing which moves from an at-rest position where no contact is made with a second terminal to a position where the ball provides contact across two terminals, thereby closing a lighting circuit.
An objection which has been made to the systems described above is that once the illumination begins, it is quite regular and predictable during the period when illumination is taking place. It is believed that the desired effect would be considerably enhanced if the illumination were to be a more accurate light display of the shoe or garment movement rather than the distorted display produced by the spring-type switch trigger.
Mercury switches are currently considered unacceptable because of the toxic nature of mercury.
It is therefore an object of the present invention to provide a switch for use with lighting systems for footwear and other clothing which provides a more accurate display rather than the controlled output of switches presently in use.
Another factor that is of considerable importance in this application, especially with children's shoes, is cost. The switch constitutes a significant part of the cost of such lighting systems, and it would be very desirable to reduce such cost. It is, therefore, another object of the present invention to provide a switch suitable for use with shoes or clothing illumination systems which is significantly less expensive than those presently in use.
One further need is to provide a simple, low-cost switch that is not subject to inadvertent closed condition when the footwear or clothing happens to be in any random orientation as on a closet floor. This result has been achieved by employing switching logic in the module. This is the result of the use of a logic circuitry which responds to a switch closure to initiate one sequence of several pulses but will not continue sequencing until the switch opens and then recloses. This simplifies the switch design so that a closed contact condition only produces one sequence and then stops until the switch opens and recloses. No guards are required for preventing a closed switch condition to drain the battery.